Carbon centered radicals reduce the density of L-type calcium channels in rat cardiac membranes.

The carbon centered radicals generated by preincubation of cumene hydroperoxide with rat cardiac membranes dose dependently reduced the Bmax of [3H]nitrendipine binding, while KD was unchanged. The reduction induced by cumene hydroperoxide was prevented by 2,6-di-t-butlyl-4-methyl-phenol. The generation of OH did not influence the [3H]nitrendipine binding; also other oxidative agents (H2O2 and HClO4) did not modify this binding. Therefore the reduction in [3H]nitrendipine binding sites is not attributable to generic oxidative stress but to the formation of carbon centered radicals.